It is known to make patch antennas where the antenna is constructed from multiple pieces, notably where the ground plane and the patch are separately constructed, and are subsequently fixed together, —see for example TW264144B and US2005146479. These antennas have separate feed networks wherever there is more than one antenna in an array, which further increases the number of components that must be assembled to form a functioning antenna system.
A technique is known in the art (patent U.S. 2005/0243527) for forming RF feed networks on a printed circuit board (PCB) by etching away unused copper, to leave only the required RF feed networks. These feed networks have not been integrated with antennas on the PCB, instead the antennas are separate items that must be suitably connected to the feed network. These feed networks are designed on the basis of removing most of the copper from the PCB, leaving only that copper required to form the RF feed network.
Separately people have made patch antennas where the radiating patch is made from a PCB or similar. These radiating elements have not been integrated with the feed network, nor with the ground plane, but instead have been separately constructed and then suitably assembled and connected. These patch antenna radiating elements are designed on the basis of removing most of the copper from the PCB, leaving only that copper required to form the RF radiating element(s).
RFID readers for conveyor belts only allow antennas to be placed around the conveyor bed and so RFID tags facing the bed may not be read as the article to which the RFID tag is attached may attenuate the signals too much. This makes RFID tags for conveyors unreliable (unless it can be ensured that all items have a desired orientation) and requires operation at high power levels which can cause interference, require shielding and provide erroneous reads from neighbouring equipment.
It would be desirable to provide a panel antenna that is simple and inexpensive to manufacture or to at least provide the public with a useful choice.
Exemplary Embodiments
According to one exemplary embodiment there is provided a method of forming an antenna comprising:                providing a first panel including a first conductive sheet secured to a sheet of dielectric material; and        forming one or more radiating elements in the conductive sheet by forming grooves in the conductive sheet.        
According to another exemplary embodiment there is provided a panel antenna comprising:                a. a panel formed of dielectric material; and        b. one or more radiating elements formed on a surface of the dielectric material by forming grooves in a first conductive sheet secured to the dielectric material.        
According to a further exemplary embodiment there is provided a panel antenna comprising:                a construction grade building panel including a sheet of dielectric material having a conductive sheet secured thereto in which parts of the conductive sheet have been removed to define radiating elements.        
According to another exemplary embodiment there is provided a method of forming an antenna comprising:                providing a construction grade building panel including a conductive sheet secured to a sheet of dielectric material; and        forming one or more radiating elements in the conductive sheet by removing portions of the conductive sheet.        
According to another exemplary embodiment there is provided a panel antenna for a belt conveyor comprising:                a. a low profile elongate panel antenna having a graduated side profile; and        b. a friction reducing layer on the surface of the panel antenna which, in use, is located adjacent the conveyor belt.        
According to another exemplary embodiment there is provided an array of panel antennas for a belt conveyor comprising:                a. a low profile elongate panel antenna having a graduated side profile;        b. a friction reducing layer on the surface of the panel antenna which, in use, is located adjacent the conveyor belt;        c. two low profile elongate panel antennas located on either side of the conveyor belt; and        d. a low profile elongate panel antennas located above the conveyor belt with sufficient height to allow objects to pass underneath.        
According to another exemplary embodiment there is provided a belt conveyor comprising:                a. a bed;        b. a belt conveyed upon the bed; and        c. a panel antenna located in a recess within the bed such that the panel antenna is located under the belt.        
According to another exemplary embodiment there is provided a belt conveyor comprising:                a. a bed formed of metal having one or more slot formed therein;        b. a belt conveyed upon the bed; and        c. a panel antenna having one or more radiating element, each radiating element being positioned to radiate using one of the one or more slots.        
According to another exemplary embodiment there is provided a method of integrating an antenna into a metal bed of a belt conveyor comprising:                a. forming one or more slot in the metal bed; and        b. placing a radiating element under each slot so as to form a slot antenna.        